Climate change poses a profound existential challenge to protected areas (Portner et al. 2021). It may decimate species and degrade ecosystem health in the short term, and in the long term the location of the protected area may become less relevant as the ranges of species and ecosystems shift. MPA management must strive to maintain the state and diversity of species, ecosystems and ecological functions within MPAs as far as possible. This will be critical to assure continued provision of MPA benefits to coastal communities, while accommodating irreversible ecological changes that will result from climate change (Hoegh-Guldberg and Bruno, 2010). 

Impacts of climate change on MPAs 

Some of the impacts of climate change on MPAs include:

Effects on species and possible responses may include: 

• Physiological and metabolic changes (i.e. acclimatizing to the new conditions)

• Behavioural changes (e.g. through changing seasonal patterns, behaviour changes affected by water flow or deoxygenation) 

• Changes in interactions (such as the symbioses of corals and zooxanthellae)

• Spatial movement or migration (e.g. down-slope to deeper waters or along-shore to higher latitudes, following specific climate belts) – marine species have been found to be shifting their ranges towards the poles about five times farther or faster than terrestrial species (Lenoir et al., 2020).

Species may not be able to undergo these changes and stay within the boundaries of an MPA, particularly a small one or one with a narrow range of habitats. Pre-existing species assemblages or communities may become unviable, and new (or in-migrating) ones more viable. MPAs that are large (so contain migration pathways) or contain a large diversity of habitats and depth ranges (providing alternative habitats locally) have greater potential to retain their biodiversity. 

Features that make an area attractive for protection, like a diverse range of habitats and species, may also confer climate resilience, but this needs to be assessed on a case-by-case basis. 

Effective protection that reduces other stresses and maintains intact biological processes may enhance the ability of species and communities to cope with climate stress and to recover. So minimizing other stresses is a primary tactic to also minimize impacts of climate change.

Beyond MPA boundaries

Effective protection within an MPA may provide important regeneration capacity to areas beyond the MPA boundaries. The greater the size or proportion protected (of a region, or habitat), the greater the effect.

The ability of species to shift with the changing climate will depend not only on the spacing and size of MPAs or intact habitats, but also on the availability of necessary conditions along the migration path. 

Climate migration

Climate migration increases uncertainty for species and ecosystems. MPAs can support successful migration by sustaining ecological health within their boundaries. They also serve as critical nodes for connectivity and sources of ecological functions such as larvae or feeding for migratory species.

Some species may benefit from climate migration, for example by migrating into areas that are already protected or that better provide a basic condition (e.g. suitable substrate).

To successfully support climate migration, however, MPAs need to address both local and climate effects, not just one or the other.

Various climate impacts beyond the boundaries of MPAs present barriers to migration:

For MPA planning at regional scales, it’s important to estimate how future climatic boundaries may shift, how these shifts may interact with existing protection zones, and what additional interventions are needed at different levels.

Ecosystem services and people

Climate-induced changes in an MPA cascade to impacts on people. Usually these changes are negative – including to the quality or quantity, certainty or long-term viability of a resource or service the MPA provides.

Some species may respond positively to climatic shifts, such as opportunistic or generalist species. However, whether this will be useful to people depends on aspects such as access and ability to harvest them, and this uncertainty may undermine resilience and sustainability of livelihoods.

Other climate impacts may be of greater significance to social resilience (e.g. droughts or flooding) or force human migration (e.g. drowning of low-lying islands), and unrelated social and/or governance shocks may override climate effects. As a consequence, conservation responses to climate change must address broader aspects of socio-ecological resilience (Ostrom 2009) and human rights (Bennett et al., 2021) (see Module 4 Indigenous engagement for climate change Q&A and Module 4 Gender, climate change and MPAs Q&A).

Reducing uncertainty

Climate change means higher uncertainty, which underscores the value of monitoring, research, and modelling to support decision-making. You can use these findings to support adaptive management. It’s important to plan and resource outreach and dissemination of new knowledge so it’s effectively used to benefit the MPA and its stakeholders.